Category Archives: Diet

Medical Podcasts: A Clinical Review Of “The Pritikin Diet” (JAMA)

JAMA Clinical Reviews LogoNathan Pritikin was a college dropout who became an entrepreneur. While doing research for the government during World War II, he observed that populations that had extremely limited food availability because of the war had substantially reduced mortality from cardiovascular disease—something unexpected at a time when cardiovascular disease was thought to be due to stress. 

After the war when food became more available CVD death rates went back up, resulting in Pritikin concluding that CVD was related to diet. Pritikin devised his own very low-fat diet that bears his name and the diet is still in use 65 years later.

Study: Maintaining Weight Loss Tied To Healthier Eating Routines Formed Over Two-Year Period

From a New York Times online article (March 16, 2020):

New York Times How To Lose Weight and Keep It Off Study March 16 2020“Maintaining weight loss can get easier over time. Over time, less intentional effort, though not no effort, is needed to be successful. After about two years, healthy eating habits become part of the routine. Healthy choices become more automatic the longer people continue to make them. They feel weird when they don’t.”

Among the useful strategies identified in the new study is to keep lower calorie foods like fruits and vegetables more accessible. “We eat what we see,” Dr. Phelan noted. The corollary is equally important: keep high-calorie, less nourishing foods relatively inaccessible and out of sight if not out of the house entirely.

The new study led by Dr. Phelan, professor of kinesiology and public health at California Polytechnic State University, identified habits and strategies that can be keys to success for millions. Yes, like most sensible weight-loss plans, they involve healthful eating and regular physical activity. But they also include important self-monitoring practices and nonpunitive coping measures that can be the crucial to long-term weight management.

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Studies: “Ultra-Processed Foods” Are 58% Of All Calories In U.S., & Obesity Epidemic’s Major Cause

From a The Guardian online article (Feb 12, 2020):

What characterizes ultra-processed foods is that they are so altered that it can be hard to recognize the underlying ingredients. These are concoctions of concoctions, engineered from ingredients that are already highly refined, such as cheap vegetable oils, flours, whey proteins and sugars, which are then whipped up into something more appetizing with the help of industrial additives such as emulsifiers. 

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From a MedPage Today online article (March 7, 2020):

The top ultra-processed foods by calorie intake were breads, beverages, cakes, Ultra-Processed Diet and Unprocessed Diet Infographiccookies and pies, salty snacks, frozen and shelf-stable dishes, pizza, and breakfast cereals.

Altogether, ultra-processed foods accounted for 58% of all calories in the U.S. diet and nearly 90% of all added sugars.

They divided foods into four categories:

  • Unprocessed or minimally processed foods: Fresh, dry, or frozen fruits or vegetables, grains, legumes, meat, fish, and milk
  • Processed culinary ingredients: Table sugar, oils, fats, salt, and other substances extracted from foods or from nature and used in kitchens to make culinary preparations
  • Processed foods: Foods manufactured with the addition of salt, sugar, or other substances of culinary use to unprocessed or minimally-processed foods, such as canned food, simple breads, and cheese
  • Ultra-processed foods: Formulations of several ingredients that — besides salt, sugar, oils, and fats — include food substances not used in culinary preparations, in particular, flavors, colors, sweeteners, emulsifiers, and other additives used to imitate sensory qualities of unprocessed or minimally-processed foods and their culinary preparations or to disguise undesirable qualities of the final product

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Health Studies: “Habitual” Supplementation Of Fish Oil (Omega-3) Lowers “All Cause Mortality” (BMJ)

From a BMJ Research study (March 4, 2020):

The BMJ podcastHabitual fish oil supplementation is associated with a 13% lower risk of all cause mortality, a 16% lower risk of CVD mortality, and a 7% lower risk of CVD events among the general population

Fish oil is a rich source of long chain omega 3 fatty acids, a group of polyunsaturated fats that primarily include eicosapentaenoic acid and docosahexaenoic acid. Initially, these compounds were recommended for daily omega 3 fatty acid supplementation for the prevention of cardiovascular disease (CVD). Consequently, the use of fish oil supplements is widespread in the United Kingdom and other developed countries.

Omega-3 Fatty Acids Cardiovascular Protection

Several mechanisms could explain the benefits for clinical outcome derived from fish oil supplementation. Firstly, the results of several studies have indicated that supplementation with omega 3 fatty acids has beneficial effects on blood pressure, plasma triglycerides, and heart rate, all of which would exert a protective effect against the development of CVD. Secondly, several trials have shown that omega 3 fatty acids can improve flow mediated arterial dilatation, which is a measure of endothelial function and health. Thirdly, omega 3 fatty acids have been shown to possess antiarrhythmic properties that could be clinically beneficial. Finally, studies have reported that fish oil can reduce thrombosis. Additionally, studies have reported that the anti-inflammatory properties of fish oil could have a preventive role in the pathophysiology of CVD outcomes. Other mechanisms could also be involved to explain the effect of fish oil on CVD outcomes.

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Diet Studies: “Eat Less, Live Longer” – Calorie Restriction Delays Age-Related Diseases (Salk)

Salk Institute logoEat less, live longer- If you want to reduce levels of inflammation throughout your body, delay the onset of age-related diseases and live longer—eat less food. That’s the conclusion of a new study by scientists from the US and China that provides the most detailed report to date of the cellular effects of a calorie-restricted diet in rats.

(Salk News, February 27, 2020)

While the benefits of caloric restriction have long been known, the new results show how this restriction can protect against aging in cellular pathways, as detailed in Cell on February 27, 2020.

Aging is the highest risk factor for many human diseases, including cancer, dementia, diabetes and metabolic syndrome. Caloric restriction has been shown in animal models to be one of the most effective interventions against these age-related diseases. And although researchers know that individual cells undergo many changes as an organism ages, they have not known how caloric restriction might influence these changes.

In the new paper, Belmonte and his collaborators—including three alumni of his Salk lab who are now professors running their own research programs in China—compared rats who ate 30 percent fewer calories with rats on normal diets. The animals’ diets were controlled from age 18 months through 27 months. (In humans, this would be roughly equivalent to someone following a calorie-restricted diet from age 50 through 70.)

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Diet Studies: Repeated “Diet Switching” Found To Increase Mortality Risks

From a Science Journal study (Feb 21, 2020):

Science Advances Feb 2020We suggest this increase in mortality seen on DR in the 4-day switch treatment is due to either accrued physiological costs or more probable, a carryover of deaths directly resulting from the rich diet, but recorded on the DR diet.

A closer examination of the timing of mortality within the 4-day switching paradigm showed that the mortality response was strongest in the second 48 hours after exposure to both DR and rich diets.

Ageing has attracted extensive scientific interest, from both a fundamental and biomedical perspective. Dietary restriction (DR) extends health and life span across taxa, from baker’s yeast to mice, with very few exceptions (12). The reduction in total calories—or restriction of macronutrients, such as protein—extends life span reliably (35). Although the precise universal mechanisms that connect DR to ageing remain elusive, translation of DR’s health benefits to human medicine is deemed possible. The widespread assumption of DR’s translational potential originates from the notion that DR’s beneficial effects are facilitated by shared evolutionary conserved mechanisms, as beneficial effects of DR are observed across taxa.

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Health: Growing Concern Over “The Obesity-Cancer Link” (The Lancet)

From a The Lancet online editorial (Feb 3, 2020):

The Lancet Endocrine and DiabetesPrevention represents the most cost-effective, long-term strategy for reducing the cancer burden and associated mortality. If provided with adequate information and support to adopt a healthy lifestyle, individuals can reduce their exposure to behavioural and dietary cancer risk factors by quitting smoking, maintaining a healthy BMI, cutting down on alcohol consumption, exercising more, and eating a healthy diet rich in fruit and vegetables. 

Although smoking is currently the major cause of preventable cancer cases and accounts for 22% of cancer deaths, a 2018 report from Cancer Research UK estimated that high BMI (overweight and obesity) now causes more cases of four common cancers (bowel, kidney, ovarian, and liver) in the UK than does smoking, and could overtake smoking as the biggest cause of cancer in women in the UK by 2043. According to WHO, in 2016, 1·9 billion adults around the world were overweight, of whom 650 million had obesity—triple the number in 1975. State-level projections for the USA paint an even bleaker picture going forward: by 2030, 48·9% of adults will have obesity; 24·2% of adults will have severe obesity; and severe obesity will be the most common BMI category among women, non-Hispanic black adults, and low-income adults. With such shocking statistics, the knock-on effect of the obesity epidemic for cancer prevention and control cannot be underestimated.

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